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ppt - University of Cambridge
... – If we can measure the rate that they are blinking then we can infer how bright they are. – Then we compare how bright they look to us and how bright they are as calculated from their blink rate. – Distance ...
... – If we can measure the rate that they are blinking then we can infer how bright they are. – Then we compare how bright they look to us and how bright they are as calculated from their blink rate. – Distance ...
Presentazione di PowerPoint
... Indeed, normal hydrogen burning stars, in the stellar core or in a shell typically behave as canonical stellar evolution models predict. And we have CMDs which are a clear evidence that globular clusters are typically populated by stars with homogeneous composition and born at the same time. ...
... Indeed, normal hydrogen burning stars, in the stellar core or in a shell typically behave as canonical stellar evolution models predict. And we have CMDs which are a clear evidence that globular clusters are typically populated by stars with homogeneous composition and born at the same time. ...
William Herschel`s Wonderful Decade, 1781-1790
... who was wasting much of his time teaching the aristocracy to fiddle. It was also evident to Banks, a skilled wheeler-dealer, how to bring about the conversion of Herschel into a full-time astronomer. Galileo had long ago exploited the unwritten rules of patronage and had named the moons of Jupiter i ...
... who was wasting much of his time teaching the aristocracy to fiddle. It was also evident to Banks, a skilled wheeler-dealer, how to bring about the conversion of Herschel into a full-time astronomer. Galileo had long ago exploited the unwritten rules of patronage and had named the moons of Jupiter i ...
Bolte_LRIS_08A
... dSph-to-dSph differences in the metallicity distributions, which suggests a wide variety of star formation and chemical enrichment histories. In the dSph there is also a strong deficiency of stars with [Fe/H]<-3.0 dex compared to the Galactic halo. These finding seem to challenge the idea that dSph ...
... dSph-to-dSph differences in the metallicity distributions, which suggests a wide variety of star formation and chemical enrichment histories. In the dSph there is also a strong deficiency of stars with [Fe/H]<-3.0 dex compared to the Galactic halo. These finding seem to challenge the idea that dSph ...
The Formation of Low Mass Stars: Overview and Recent
... observe the infalling gas in redshifted absorption against the background protostar Very high spectral resolution (<0.1 km/s) is required High sensitivity to observe in absorption against disk. ...
... observe the infalling gas in redshifted absorption against the background protostar Very high spectral resolution (<0.1 km/s) is required High sensitivity to observe in absorption against disk. ...
Academia Sinica Press Release
... images translated into rich results and their implications in binary studies,” says Dr. Alfonso Trejo (ASIAA, Taiwan), a co-author of the study. Binaries in elliptical orbits for stars in late stellar evolutionary phases may be ubiquitous over a large period range. Many planetary nebulae – stars tha ...
... images translated into rich results and their implications in binary studies,” says Dr. Alfonso Trejo (ASIAA, Taiwan), a co-author of the study. Binaries in elliptical orbits for stars in late stellar evolutionary phases may be ubiquitous over a large period range. Many planetary nebulae – stars tha ...
Introduction to Astrophysics, Lecture 13
... While there is no doubt more material in the form of cold gas waiting to be made into stars, it is not believed that that will explain the difference. Instead, it is believed that most of the material in the galaxy is a new form of matter, known as dark matter. So far, we have little idea what form ...
... While there is no doubt more material in the form of cold gas waiting to be made into stars, it is not believed that that will explain the difference. Instead, it is believed that most of the material in the galaxy is a new form of matter, known as dark matter. So far, we have little idea what form ...
Document
... We have a unique data set that offers unprecedented temporal coverage of >1600 stars down to 19th magnitude, yielding a detection of variability in about 8% of the field stars. Have measured eclipsing binary periods down to tenths or hundredths of a second. Variation in orbital parameters gives info ...
... We have a unique data set that offers unprecedented temporal coverage of >1600 stars down to 19th magnitude, yielding a detection of variability in about 8% of the field stars. Have measured eclipsing binary periods down to tenths or hundredths of a second. Variation in orbital parameters gives info ...
Stellar Luminosity and Mass Functions * * * * * History and
... Massive stars have short lifetimes Suppose we observe the luminosity function of an old cluster. There are no very luminous main sequence stars. But this does not mean that the IMF of the cluster had zero massive stars, only that such stars have ended their main sequence lifetimes. More generally, ...
... Massive stars have short lifetimes Suppose we observe the luminosity function of an old cluster. There are no very luminous main sequence stars. But this does not mean that the IMF of the cluster had zero massive stars, only that such stars have ended their main sequence lifetimes. More generally, ...
Understanding Mass-Loss and the Late Evolution of Intermediate
... New Mexico, first light in 2010), with resolutions ranging from 0.1 to 100, can be used to probe the launch regions of CFWs in late AGB stars and PPNs, in particular the disk temperature, geometry and density structure. Direct imaging, with space-based telescopes such as HST and JWST will remain uns ...
... New Mexico, first light in 2010), with resolutions ranging from 0.1 to 100, can be used to probe the launch regions of CFWs in late AGB stars and PPNs, in particular the disk temperature, geometry and density structure. Direct imaging, with space-based telescopes such as HST and JWST will remain uns ...
Variable Star Observation
... stellar system consisting of two stars orbiting around their center of mass. ...
... stellar system consisting of two stars orbiting around their center of mass. ...
Debris Belts Around Vega
... “transit” method since they wouldn’t pass in front of the star from our perspective. We can’t detect planets by the “Doppler” method because stars like Vega rotate very fast and have very few narrow lines in their spectra for noticing the tiny shifts in line position caused by the gravitational tugs ...
... “transit” method since they wouldn’t pass in front of the star from our perspective. We can’t detect planets by the “Doppler” method because stars like Vega rotate very fast and have very few narrow lines in their spectra for noticing the tiny shifts in line position caused by the gravitational tugs ...
Sample Exam for Final (with correct answers)
... (e) how much of the matter in the universe is Dark Matter, and how much is ordinary matter 31. In class I spoke about the concept of “Dark Energy”. The reason for thinking Dark Energy exists is observations which show (a) a lack of visible light in the outer parts of large spiral galaxies. (b) the ...
... (e) how much of the matter in the universe is Dark Matter, and how much is ordinary matter 31. In class I spoke about the concept of “Dark Energy”. The reason for thinking Dark Energy exists is observations which show (a) a lack of visible light in the outer parts of large spiral galaxies. (b) the ...
The First Stars in the Universe
... sources such as quasars. Future observations of distant objects may help determine when the universe’s helium was ionized. If the first stars were indeed very massive, they would also have had relatively short lifetimes—only a few million years. Some of the stars would have exploded as supernovae at ...
... sources such as quasars. Future observations of distant objects may help determine when the universe’s helium was ionized. If the first stars were indeed very massive, they would also have had relatively short lifetimes—only a few million years. Some of the stars would have exploded as supernovae at ...
LIDAR Imaging Detector Could Build `Super Road Maps` of Planets
... mission of identifying massive stars and clusters in the galactic center. These augment our instrumentation development on two of the most important science missions for the next twenty years: the Large Synoptic Survey Telescope (LSST) and the Supernova Acceleration Probe (SNAP). On both missions, t ...
... mission of identifying massive stars and clusters in the galactic center. These augment our instrumentation development on two of the most important science missions for the next twenty years: the Large Synoptic Survey Telescope (LSST) and the Supernova Acceleration Probe (SNAP). On both missions, t ...
Astronomy HOMEWORK Chapter 15 1. Where in the Galaxy is the
... point thousands of LY away in the direction of Sagittarius. He correctly reasoned that the globular clusters would form a roughly spherical distribution about the center of the Galaxy. 10. Why do astronomers believe that vast quantities of dark matter surround [and pervade] our Galaxy? First, the da ...
... point thousands of LY away in the direction of Sagittarius. He correctly reasoned that the globular clusters would form a roughly spherical distribution about the center of the Galaxy. 10. Why do astronomers believe that vast quantities of dark matter surround [and pervade] our Galaxy? First, the da ...
–1– 28. HIGH-MASS STAR FORMATION: THEORY 28.1. The Effects
... approximately include the self gravity of the gas, the accretion rate is indeed about c 3 /G.) Bonnell and collaborators have proposed two alternative models. In the competitive accretion model (Lecture 24), small stars (m∗ ∼ 0.1M¯ ) form via gravitational collapse, but then grow by gravitational ac ...
... approximately include the self gravity of the gas, the accretion rate is indeed about c 3 /G.) Bonnell and collaborators have proposed two alternative models. In the competitive accretion model (Lecture 24), small stars (m∗ ∼ 0.1M¯ ) form via gravitational collapse, but then grow by gravitational ac ...
Resolved SPs : simulations
... The description of the details in the shape of the tracks, and the evolutionary lifetimes (use normalized independent variable) The description of photometric errors, blending and completeness (evaluate crowding conditions: if there is more than 1 star per resolution element the photometry is bad; c ...
... The description of the details in the shape of the tracks, and the evolutionary lifetimes (use normalized independent variable) The description of photometric errors, blending and completeness (evaluate crowding conditions: if there is more than 1 star per resolution element the photometry is bad; c ...
Astronomers Find The Most Distant Star Clusters Hidden Behind A
... discovered the most distant population of star clusters ever seen, hidden behind one of the nearest such clusters to Earth. At a distance of more than a billion lightyears, the newly discovered star clusters provide a unique probe of what similar systems in our own galaxy once looked like. See also: ...
... discovered the most distant population of star clusters ever seen, hidden behind one of the nearest such clusters to Earth. At a distance of more than a billion lightyears, the newly discovered star clusters provide a unique probe of what similar systems in our own galaxy once looked like. See also: ...
Powerpoint for today
... - at least 30 kpc across - contains globular clusters, old stars, little gas and dust, much "dark matter" - roughly spherical ...
... - at least 30 kpc across - contains globular clusters, old stars, little gas and dust, much "dark matter" - roughly spherical ...
Lecture 7 Evolution of Massive Stars on the Main Sequence and
... The convective core shrinks during hydrogen burning During hydrogen burning the mean atomic weight is increasing from near 1 to about 4. The ideal gas entropy is thus decreasing. Also convection is taking entropy out of the central regions and depositing it farther out in the star. As the central en ...
... The convective core shrinks during hydrogen burning During hydrogen burning the mean atomic weight is increasing from near 1 to about 4. The ideal gas entropy is thus decreasing. Also convection is taking entropy out of the central regions and depositing it farther out in the star. As the central en ...
Progenitor stars of supernovae
... Energetic explosions in the universe Energy emitted 1051 ergs (1029 times more than an atmospheric nuclear explosion) One SN explosion shines brighter than the host Galaxy In universe few supernovae explosions every second ...
... Energetic explosions in the universe Energy emitted 1051 ergs (1029 times more than an atmospheric nuclear explosion) One SN explosion shines brighter than the host Galaxy In universe few supernovae explosions every second ...
The Effective Temperature and the Absolute Magnitude of the Stars
... As it can easily be seen, the matching is complete when the effective temperatures are equal. When they are not, the differences start at the third decimal place. Therefore, it is consideredthattheworkinghypothesisisvalidandveryusefultoclosetheproposedtheory. ...
... As it can easily be seen, the matching is complete when the effective temperatures are equal. When they are not, the differences start at the third decimal place. Therefore, it is consideredthattheworkinghypothesisisvalidandveryusefultoclosetheproposedtheory. ...
here
... Bending and stretching vibrations of hydrocarbon bonds • Comparison with laboratory IR spectra • But conditions very different (ionized, isolated) ...
... Bending and stretching vibrations of hydrocarbon bonds • Comparison with laboratory IR spectra • But conditions very different (ionized, isolated) ...
Planetary nebula
![](https://commons.wikimedia.org/wiki/Special:FilePath/NGC6543.jpg?width=300)
A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word ""nebula"" is Latin for mist or cloud and the term ""planetary nebula"" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.